The present invention relates generally to surface finishing, and more particularly to an apparatus which utilizes random orbitals to finish the surfaces of solid material including wood, plastic, and metal.
In many manufacturing processes, it is necessary to sand, grind, and/or polish wood, metal and synthetic material to create a finished surface ready for installation. Such materials may be used to ultimately create products such as shelves, cabinets, furniture, counter-tops and the like. One of the more difficult materials to finish is what is becoming commonly referred to as solid surface materials or as plastic solid surface materials (PSSMs). These are polymer based building materials typically manufactured and sold in sheet form and used to form counter-tops and the like. The most widely recognized of which is the so-called "Corian" material manufactured by DuPont.
Although the present invention may be described as it pertains to the finishing of PSSMs, it will be understood that it is not to be construed as limiting thereto. In fact, it has been found that the present invention finishes metal, wood and other plastic materials with an equally superior effectiveness.
Various machines have been designed to enable the sanding and/or finishing of materials to be done automatically rather than by hand. The early of these such machines typically used a belt sander of some sort. The material would enter the machine, be passed under this belt sander by some means, and exit the machine with what was hoped to be a finished surface. However, the exiting material typically had sand lines where the edges of the belt sander ran along the material and/or rough areas where the belt sander ran opposite the grain when sanding wood materials. To remove these imperfections, additional finishing often had to be done by hand with a hand-held sander or with steel wool.
To alleviate these problems, the next generation of automatic sanders began to orbit the abrasive rather than merely running it back and forth over the material. This, it was hoped, would remove any sanding patterns and eliminate the finish sanding to be done by hand. The most common of such machines includes an elongated abrasive covered platen generally extending the width of the machine. This platen may move in one or two orbits. One created by the rotation of its connecting shafts and the other by the rotation of a brace connecting the shafts. This dual rotation more accurately simulates the motion of sanding by hand.
Although this dual rotating platen may help reduce sand lines and rough areas, it is expensive to manufacture and maintain. Additionally, for this type of sander to function properly, the incoming materials have to be of similar tolerances. Thus, PSSMs are still finished by hand held power sanders known as random orbital sanders.
The basic construction of random orbital sanders typically comprises a motor for driving a balanced shaft for rotational movement about a first or driven axis, and a bearing device for coupling a sanding pad or disc to the balanced shaft for rotational movement relative thereto about a second axis disposed in an offset or parallel relation to the first axis. During operation of this type of sander, the sanding pad is forced to move along a circular path disposed concentrically of or to orbit relative to the first axis, while being free to rotate relative to the second axis.
These random orbital sanders have always been popular in the automotive industry, and, now, they are currently the best way to remove scratches, marks and other imperfections from the relatively hard surfaces of PSSMs. However, these random orbital sanders are hand held sanders and, as such, have certain drawbacks, the most obvious of which is that they are hand held and require a great deal of workmen's time to adequately run the sander over the subject material. Additionally, the manual guidance of these sanders may produce an uneven finish across the material's surface or perhaps a mild bevel effect due to disproportionate sanding.
In view of the aforementioned needs and the shortcomings of the prior art, it is therefore an object of the present invention to provide an apparatus that overcomes the deficiencies of the current practices whereby an apparatus is provided for finishing solid materials with a minimum amount of labor with maximum efficiency at a minimum cost.
It is another object of the present invention to provide an apparatus capable of effectively finishing the relatively hard surfaces of plastic solid surface materials.
Still another object of the present invention is to provide an apparatus for automating sanding work currently performed by hand.
It is yet another object of the present invention to provide an apparatus for providing a finished product having a relatively proportionately even degree of smoothness throughout its surface.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.